VFC M4 wiring harness problem

[Jackarutu]

I thought I would take the time to write up my experience I encountered while trying to use a VFC switch in a version 2 clone gearbox. Perhaps it will save someone else from the problem I ran into.

First I had ordered some of the VFC wiring harnesses as used on their 2009 series M4s. These don’t have any connection to the selector interlock.

Originally when I ordered these I thought I was getting just the switch and planned on using them with a MOSFET installation. When I saw they were a complete wiring harness wired to the front I cast them aside and forgot about them until I was rebuilding a gearbox with a very badly chewed wiring harness and so I grabbed one of the VFC ones from stock and installed it.

I put the gearbox together and installed in the lower receiver and added the hand grip and motor and went to test it. I pulled back on the trigger and the piston moved a little and stopped. I pulled the trigger again and the piston moved a little further back and stopped again. Then for some reason (I can’t really say why I did it) I pulled the trigger half way back and stopped there and the gearbox fired one complete round. Then I pulled the trigger all the way back and same result of the piston moving just a little and stopping.

I removed the battery and sat there pulling the trigger back and releasing it. And then suddenly I realized I was hearing a clicking sound after I pulled the trigger all the way back.

Dissembled the gearbox and removed everything except the wiring harness and the trigger. Held the trigger in place and pulled it back. When I did this I saw that after the trigger came all the way back and the switch went all the way forward that the trigger was slipping down and past the switch allowing the switch to spring back to the off position.

I replaced the wiring harness with a different brand and all is well with my problem but it leaves me wondering if VFC has a different casting for their triggers that work differently with their switches? I can't really say what trigger I was using except it was a TM clone such as one finds on a JG product.

From time to time when I order triggers for use in M4/M16 I have ordered G&G, Mad Bull, CA, Echo1, etc and never had a problem like this before. For all I know all these trigger are cast at the same foundry in China or Taiwan and then sold under many different brand names.

Anyway that’s my story and I hope it helps someone else if they find themselves in the same boat.

[Sha Do]

Good info bro.

VFC appears to be a very good quality clone of KWA, where in I also found an issue with the electrical set up.
The selector switch thing is bypassed in a lot of the clone models (it just bypasses an internal safety that works with the mechanical locking of the trigger in safe).
Anyways, with KWA I found that the mold for their internal trigger switch assembly is different in two aspects (so I am assuming that the same is true for VFC). One, it is slightly smaller, but thicker than a traditional assembly (such as a TM). Two, it sits slightly off mounting, and is difficult to seat in a different brands of the version 2 boxes. It has nothing with the actual trigger, but if the alignment of the switch is not perfect, you're gonna have that problem.

I guess it's just their way of making customers use their brand of internals.

SHA DO